Pathology · patient case question
Clinical examination of the gingiva overlying that same region shows a flat, blue-grey, non-blanching macule. What is the most likely diagnosis?
Patient case: Routine radiographic survey
Patient: Male, 34 years old
Chief complaint: “I'm just here for my check-up.”
History: No significant medical history. No medications. Last radiographs five years ago.
Findings: A panoramic radiograph and a full-mouth periapical series are taken today. Several incidental findings are noted for discussion.
Show answer and explanation
Correct answer: A. Amalgam tattoo
- A. CORRECT. Amalgam tattoo is metal debris driven into the mucosa during restorative or surgical procedures. It is flat, blue-grey to black, asymptomatic, does not blanch, and does not change over time. Larger particles are visible on a radiograph as fine radiopaque flecks — which is exactly the correlation being tested here. When particles are radiographically demonstrable, biopsy is unnecessary.
- B. Oral melanoma is a genuine concern for any pigmented lesion, but it is typically raised or ulcerated, irregular and asymmetric in outline, and enlarges. A flat blue-grey macule with radiopaque flecks in a restored area does not fit.
- C. A varix is a dilated vein, most often on the ventral tongue or lip, which is compressible and BLANCHES on diascopy.
- D. An oral melanotic macule is brown rather than blue-grey, arises from melanin rather than metal, and has no radiographic correlate.
Note: Rule of thumb: a pigmented lesion with matching radiopacities is an amalgam tattoo. A pigmented lesion with NO radiographic correlate that is growing, raised or irregular gets a biopsy.